Discuss biological approaches
Explanations of the biological basis of
personality operate at several levels,
from “distal” to “proximal”
◦ Neural systems
◦ Neural structures
◦ Neurochemicals
Discuss the genetics of personality
DNA as source of our similarities & differences
Discuss family studies
Examine resemblance between family members as a function of genetic relatedness
Discuss limitations of family studies
BUT: genetic contributions are confounded with shared environmental contributions
Discuss twin studies
Compare resemblance between monozygotic (MZ) & dizygotic (DZ) twins
MZ twins are 100% related, DZ twins 50% related
Greater resemblance for MZ twins implies genetic contribution
Environments are equally similar for both kinds of twin, so environmental factors are not confounded
Discuss limitations of twin studies
BUT: possibility of more similar environments for MZ twins,
& perhaps twins are unrepresentative
Discuss adoption studies
Compare resemblance of adopted children to adoptive parents (APs) & biological parents (BPs)
APs are 0% related but supply environment, BPs are 50% related
Degree of resemblance to APs & BPs shows environmental & genetic contributions
Discuss limits of adoption studies
BUT: adoption must occur early; problem of selective placement; biological mother provides prenatal environment as well as genes
Discuss heritability (including statistic for personality characteristics)
Behavioural genetic studies yield estimates of heritability = proportion of variance in the trait accounted for by genes
*e.g., .8 for height, .7 for weight, .5 for maths aptitude, psychological/personality characteristics almost always .4
Most personality attributes show heritabilities from .3 to .5
This is even true for apparently purely learned attributes (e.g.,
political attitudes, vocational interests)
What are some issues/caveats of heritability?
Describe the role of the environment
Behavioural genetics clarifies the role of the environment
‘Shared’ environmental influences (those that make siblings more similar) tend to be weak
‘Non-shared’ environment influences (those that make siblings more different) tend to be much stronger
Environmental factors can themselves be genetically influenced
Discuss the idea of shared vs non-shared environments
“salient environmental effects do not make siblings similar.
That is, they are not shared by children growing up in the
same family.”
“theories of socialization had assumed that children’s
environments are doled out on a family-by-family basis. In
contrast, the point of non-shared environment is that
environments are doled out on a child-by-child basis.”
Discuss the concept of specific, personality related genes
Heritability says nothing about specific genes or genetic mechanisms
Several specific genes have been identified in candidate gene studies, but they do not replicate
Most traits appear to be influenced by hundreds of genes,
each with very small effect
note: study found around 190 genes effect one trait of neuroticism
Discuss brain functioning: systems, Eyesenck’s theory
Eysenck’s theory
Extraversion & low cortical
arousal
Discuss brain functioning: systems, Gray’s theory
Impulsivity & “behavioural activation system” (BAS)
◦ Linked to sensitivity to reward & pleasure
◦ Associated with a tendency to approach rewards
Anxiety & “behavioural inhibition system” (BIS)
◦ Linked to sensitivity to punishment & pain
◦ Associated with a tendency to avoid punishments
Discuss brain structures
Some links have between found between
Big 5 & the size (volume) of brain structures
However, a recent meta-analysis suggests these links are questionable
A more promising direction is exploring patterns of functional activity and connectivity in the brain
Discuss extraversion and neuroticism in terms of brain structures
Neuroticism
Extraversion
Discuss the chemicals of brain functioning
Personality factors may be associated with
neurotransmitter activity in the brain
Extraversion & dopamine levels
Discuss hormonal factors
There is evidence that personality is influenced by prenatal exposure to sex hormones Ratio of 2nd (index) to 4th (ring) finger (2D:4D) is associated with testosterone exposure
Lower ratio in men than women, especially on right hand i.e., men tend to have longer ring finger than pointer finger
Among men, lower 2D:4D ratio correlates with:
What are some Cognitive explanations for personality?
Explain personality with reference to cognitive processes & structures
◦ Thoughts, plans, memories, beliefs, strategies
Focus on ways of thinking & the construction of meaning◦ Having versus doing
◦ People as active sense-makers
◦ Emphasis on ‘experience-near’ phenomena
◦ Motivation to understand & predict
◦ Person-as-scientist model
What are the 4 cognitive approaches?
We will examine four approaches
◦ Perceiving (personal constructs)
◦ Explaining (attributional style)
◦ Thinking (emotional intelligence)
◦ Representing (the self
Discuss George Kelly’s personal constructs
George Kelly proposed that humans are primarily driven to understand, predict &control their environment
We develop ‘theories’ to do so
He called these theories ‘personal constructs’
To Kelly, human cognition is contrastive
Each person has a system of constructs in terms of which they perceive the world
This system of constructs is the personality
This is a radical approach
What is The Repertory Grid?
A qualitative and quantitative interview method, developed by George Kelly, that explores how an individual perceives and makes sense of their world. It involves eliciting personal constructs (dichotomies of meaning) by comparing a set of “elements” (such as people, objects, or events) and then uses this information to create a grid or matrix that maps the relationships between the elements and the constructs.
Basically has people listed on it and you have to describe how two of them are different to a third person and refer to the difference
What are Construct systems?
Constructs can be analysed in many
ways to generate a ‘map’ of the
individual’s construct system